5x + y = 9....multiply by 7
10x - 7y = -18
----------------
35x + 7y = 63 (result of multiplying by 7)
10x - 7y = -18
----------------add
45x = 45
x = 45/45
x = 1
5x + y = 9
5(1) + y = 9
5 + y = 9
y = 9 - 5
y = 4
solution is : (1,4)
=========================
-4x + 9y = 9
x - 3y = -6 ....multiply by 4
----------------
-4x + 9y = 9
4x - 12y = -24 (result of multiplying by 4)
---------------add
- 3y = - 15
y = -15/-3
y = 5
x - 3y = -6
x - 3(5) = -6
x - 15 = -6
x = -6 + 15
x = 9
solution is : (9,5)
V = lwh
15(10.5)(4.5) = 708.75
X=first week
y=second week
z=third week
t=fourth week
18 more one 2nd week than 1st
x+18=y
x=y-18
3rd week, 4 less than 2 times as second
z=2y-4
4th week, 92
ttal=382
x+y+z+t=382
sub waht we know
x=y-18
y=y
z=2y-4
t=92
y-18+y+2y-4+92=382
conbine line terms
4y+70=382
minus 70 boht sides
4y=312
divide both sides by 4
y=78
78 customers
for equation read my answer slowly
The answer is 24. You subtract 40 - 16.